Oil picks (including Gear Oil) and suggestions by forum members
Switching to Synthetic over 100,000 miles
Oil Viscosity
How to Read Oil Weights
On High Mileage Oil
Oil Analysis
Oil Grouping Discussion
Oil Filters
Links on Oil Topics
General Oil Discussions - This is 3 years of posts, opinions and other tidbits from cary and RavenTai
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Updated June 2007 to include a discussion on Change in Dexron ATF, see Post #28

The majority of this FAQ comes from Cary and RavenTai and the 80’s forum would like to thank them for their continued support. We have taken their posts over the last three years to multiple questions and placed them in this FAQ. In fact, 90% of this FAQ was developed from extracting their posts from 3 years and compiling the information. They also provided input and a review before release of this FAQ. It should be noted that the majority of the information from RavenTai and Cary reflects their time spent looking at used oil analysis (UOA’s), discussions, and MSDS sheets on the various products. Our recommendations are based on oils that have consistently performed well in UOA’s, their availability, and pricing.

Telling someone which is the best oil is like telling someone which is the best Ice Cream. There is no one true answer. Everyone has a different opinion. However, this forum has two individuals who would count as oil experts. This thread contains their and other forum members Opinions and should be used as such. There is a lot of discussion on bobistheoilguy.com and you can always search there as well.

​

Current Favorites are:

Synthetic:​

1) Mobil 1 0w-40. This is a great oil, but some have had high consumption with it, others can't find it.

22) Mobil 1 Turbo Diesel Truck 5w-40 (Formerly Mobil 1 Truck & SUV 5w-40). I know that it says Diesel, ignore that part. It is relabeled Mobil Delvac 1, and designed as a fleet oil (gas and diesel engines). Many believe that this is the best oil in the Mobil 1 lineup.

3) Castrol 0w-30 aka German Castrol (THIS OIL APPEARS DISCONTINUED SO LOOK CAREFULLY AT THE BOTTLES BEFORE YOU BUY). You have to be careful with this one as there are two versions, a US made Group III and a German Made Group IV oil. If you want to run this one you have to look carefully at the back of the bottle for those magic words "Product of Germany" or "imported from Germany". The back will also carry BMW LL-01, MB 229.3 and 229.5 approvals.

4) Shell Rotella T 5w-40 Synthetic. This is a group III oil that has turned in consistently good results at bobistheoilguy.com. It is the value leader of the bunch when you can get it at Walmart for $12.88 per gallon. If you have to buy it at $5.00 a quart, buy one of the others above.

5) Mobil 1 Hi Mileage 10w-40. This is a newcomer and availability has been sparse but it should be a great choice and work well when it can be found.

6) Mobil 1 High Mileage 10w-30. MAKE SURE IT IS THIS EXACT MOBIL 1 10W-30 SINCE THEY HAVE 3 DIFFERENT VERSIONS. Yes, I know that I said no Mobil 1 30 weight oils, so why this one? This one, like the German Castrol, is formulated on the heavy end of the 30 weight scale and meets ACEA A3 specs (HTHS of 3.6).

Right now some Mobil 1 is still on shelves that was produced post Katrina outside of their API approved recipe due to not being able to get some of the normal components of this oil, this oil will be marked on the back left "suitable for" and will not have the API Doughnut, the regular stuff is starting to come back on shelves but I cannot get it in my weights locally yet.

I am not sure what exactly is different but if you have a choice get the non "suitable for" bottles.

​

Mineral (Dino) Oil:​

The major brands are all getting pretty good. If you are in a mild climate (temps above 40F), the Chevron Delo 400 15w-40 appears unbeatable, and many times turns in numbers close to the synthetics. For those in colder climates, in the winter, run a 5w-30 if you use mineral and pick your choices from Chevron, Havoline, Pennzoil, or Mobil. The only reason I don't mention castrol GTX is their mineral oils seem to have pretty crummy low temp pump specs. Valvoline is excluded because their All Climate has shown poor performance, but the Maxilife is supposed to be pretty good and is available in 5w-30.

I was always a Valvoline fan, but after reading the oil analysis (actual testing of oil run in cars), I was surprised at how poor Valvoline performed compared to some other dino oils. On average the two best performing dino oils are 1) Chevron Supreme, and 2) Penzoil Purbase. I had heard good things about Chevron oils before, but prior to this had never heard good things about Penzoil. BTW, Chevron is available at Costco.

Many people will start to discuss sludge when Penzoil is mentioned, usually saying something like “my mechanic says Penzoil causes sludge problems.” Penzoil and other Pennsylvania crudes have had problems with sludge. The thing is these problems were 30+ years ago when they were group I oils with 1970’s additive packages. Sludge has not been a problem with these oils for a long time and do not merit any further discussion because the problems were so long ago. Also, note that Penzoil and Quaker State are the same company and their oils are usually identical.

Switching to Synthetic Oil in Higher Mileage Vehicles
Does switching from a petroleum-based oil to a fully synthetic oil on a higher mileage vehicle (75,000 miles) have any harmful effects? I've heard that the synthetic oil, because it is cleaner, may actually loosen some of the build-up from petroleum oil and has the potential of clogging the pump. Is this true or does one simply need to change the filter more frequently for the first few thousand miles after switching? Thanks
-- Michael Ritzke, Appleton, WI

When switching to Mobil 1 in higher mileage vehicles, we recommend an initial short (2,000 to 3,000 miles) oil change, both oil and filter. This will allow Mobil 1 to clean some of the engine deposits that have accumulated over time. Following this initial short oil change, continue with your normal oil change interval.​

You should be fine switching to synthetic, I have done so on several cars with over 100,000 miles with no problems (in one I even had lower oil consumption). The reason that you hear that you shouldn't switch on high mile cars comes from the original Mobil 1 back in the 80's when they didn't put a seal sweller in the oil. With older cars that had marginal seals the extra cleaning in the Mobil would flush all the gunk out and they would leak like mad. Once mobile started to put the seal swell in, the problem went away.

Viscosity is a measure of the resistance of a fluid to deformation under shear stress. It is commonly perceived as "thickness", or resistance to pouring. Viscosity describes a fluid's internal resistance to flow and may be thought of as a measure of fluid friction. Thus, water is "thin", having a low viscosity, while vegetable oil is "thick" having a high viscosity.

Celsius
-7 to 38___20w50
-10 to 38__15w40
-18 to 38__10w30
-30 to 8___5w30

Here are my (Cary's) thoughts

Straight weight oil- Don't waste your time. There is no advantage

20w-40- Not any thicker than 0w-40, 5w-40, 10w-40. For extraordinarily hot climates you would step up to a xw-50 oil (there shouldn't be a need though). The reason that you don't see 20w-40 anymore is that the other multi viscosity oils take its place. So why did it ever exist? Because back in the dark ages of multiviscosity oils, the viscosity modifiers and pour point depressants needed to make a mineral oil multiweight would break down quickly and cause sludge. The wider the oils weight span the more modifiers needed the more sludge created. In the past 30 years the base stocks for mineral oil and the viscosity modifiers and pour point depresants have improved considerably. Today there is really no problem with sludging from viscosity modifiers and pour point depresants. They still break down, but much slower and without the crud left behind. Synthetics tend to need less of these additives and it is widely speculated that Mobil 1 10w-30 does not in fact have any viscosity modifiers or pour point depresants (note this is different than detergent)

…..When looking at oil, the first number refers to how the oil acts when cold , i.e. 0w means it pumps like 0 weight oil when it is 30 below, 5w like five weight, 10w like 10 weight and so on. The second number refers to how the oil acts at operating temperature and is the real weight of the oil. So when you look at Honda (and Fords) the 0W-20 oil acts like 20 weight oil when hot. 10w-30 acts like 30 weight when hot. 0w-40 acts like 40 weight when hot and give greater film strength and is thicker than 30 weight. It is entirely different than the honda oil.

There is a reason that you have not seen oil like 0w-40 until recently. In order to get a mineral oil to act as a multiweight, you must add viscosity enhancers which break down over time. The wider the spread, the more modifiers. Synthetic, because the base stock is much more stable, does not require nearly the amount of modifiers to be multigrade. Example Mobil 1 10w-30 does not require viscosity modifiers to be multigrade. With the new synthetic formulas it takes very few modifiers to meet the 0w-40 spec, and the oil is stable.

The new 0w-40 Mobil 1 is one of the few oils that meets the very strict MB 229.5 spec, and is factory fill for Porsche and Mercedes. Cars from Europe have used heavier, and continue to use heavier oil, due to the higher sustained speeds and heavier loads that their engines are subject to (Think about a 1.8 liter 130 horsepower car running full throttle on the Autobahn for hours, versus an American V-8 running at 80 mph for hours, big difference in load).

​

You should also be aware that not all synthetics are created equal. Apparently there are Type I, II, III, IV and V base stocks. Many “Synthetic” oils are taken from Type II & III stocks. Mobil 1, certain Shell and other oils sold in Europe are made from only Type IV & Type V stocks. Supposedly, Mobil 1 is the only oil sold in the US made from these superior base stocks (I should note that Redline and Amsoil supposedly use these better stocks, but neither meets the latest A5, 229.3, or 229.5 specs)

Hi mileage oils are typically a heavy in grade oil (i.e. heavy end of the 30weight range, heavy end of the 40weight range) with extra additives to help seal sweals and stop leaking. Also many are a synth blend. My thoughts, you are getting some benefits for the extra money, but if I were to use a Semi-synth, I would go for the new Mobil Drive Clean Plus

First thing you should do is find a Virgin oil analysis of that oil telling what it started with, with this you can see what was added and what was lost, unfortunately oils change often, especially lately with the new API grade “SM”, a virgin sample is only comparable if it is recent.

The exact alloys of all parts of the 1FZ-FE are not known to me but wear metals and their possible sources are listed below
Iron: cylinder walls, piston rings, crank, wrist pin, cams (including lobes and gears) valve shims & buckets, oil pump and associated gearing and timing chain,
Aluminum: pistons, cam journals, oil pump cover, timing cover and possibly timing chain slipper,
Chromium: possibly in piston rings or other iron/steel parts.
Lead: alloy in crank bearings
Tin: alloy in crank bearings & possibly elsewhere
Copper: alloy in oil pump drive bushing & possibly elsewhere
Silicon: usually from the environment as dirt, but can also weep from sealants, if you have high Silicon and high insolubles and wear metals it generally means poor air filtration.

Oil is grouped by the American petroleum institute by qualities of the base stock (a quart of oil is mostly base stock with additives to improve the abilities of the base stock)

Group I is oil with a lot of contaminants
Group II is oil that is relatively clean (most standard oil is in this category)
Group III is same as group II except it has a good viscosity index ( its viscosity does not change as much with changes in temperature) usually made of severely hydrocracked mineral oil (dino) ,
Group IV is PAO (Polyalphaolefin) it starts as propane, the propane molecules are uniformly put together to make larger molecules of oil, the manufacturer gets to basically build the hydrocarbon molecule with the properties they want and every molecule is identical. Where as mineral oil is a collection of many types and sizes of hydrocarbon molecules and contaminants
Group V anything else, mainly exotic synthetics, most well known in this group is Redline (mail order/speed shops) witch has an ester base, many turbine engine oils are also in this group

A few years ago Castrol stopped buying PAO base oil from Mobil and started using Group III as the base for their Syntec line of “synthetic” oil, Mobil complained that they were marketing mineral as synthetic and it wound up in arbitration unfortunately Castrol won by showing it was better than dino oil and they needed a way to market that difference to the public, now most of the other oil companies followed suit, heard recently that one of the other over the counter brands went back to PAO (Penzoil? Quaker State? cant remember, and don't know if it is true) the castrol syntec 0w30 red label imported from Germany is suppose to be something good (group IV or V) the yellow label 0w30 is same group III, 0w30 is to thin for me In GA, but anyway other than a few odd balls Mobil 1 is the only commonly availably true synthetic

the group III “synthetics” are good oils but you are paying full synthetic price for something less than synthetic ability, if you are going to get mineral oil that was marketed as synthetic might as well by normal oil and save a lot of money as it works just fine

Rotella T syn is not as bad a deal it is only slightly more than dino when you buy it by the gallon at Wally world

Mobil 1 is still a Group IV PAO oil. The thread about Mobil 1 not being pops up about every two weeks and is promptly disproved. If you search Mobil's site they still have a whole thing about why PAO is superior, why they don't use Group V POE base stocks, and that they use PAO.

As far as Rotella Synth, you are correct is not a “;true”synthetic according to Europe's standards as it is a Group III Hydrocracked. That said, it has been turning in great wear numbers (as have some of the other group III oils) and at $12.84 a gallon at Walmart is a good deal. Since rotella Synth is a HDEO it should have no problem going 8,000 miles per change, especially with the 8 quart sump in the LC.

( The below items are highlights of 3 years of posting by Cary and RavenTai)

Mobil 1 10w-30 is to thin (thinner than ideal).

There is really no point in running 20w-50, it is slow to lube on startup and is thicker than needed. The general idea is run the lightest oil that provides adequate protection. It appears in most cases that the heavy 30 weights/light 40weights hit this mark best, providing the lowest wear numbers in most motors, protection of the cams and bearings in all circumstances, while not unduly lowering fuel economy and power output

The EPA requirements are even more strict than what you were told. The EPA now requires that manufactures 1) fill the autos with the oil that they are tested with, 2) list the weight used as the recommended weight, and 3) sign a sworn statement (I don't know what the penalty is for violating it) that their dealers will use the weight of oil recommended.

After all of my research I have come to the conclusion that we should look at what the Europe/Austrailian recommendations are for oil weight when the same engine is used worldwide. I will note again that he Aus spec says you can use 10w-30, 15w-40, and 20w-50 up to 100F.

Mobil 0w-40 appears to be the best choice for worldwide use. My only potential concern (and this is the footnote to a footnote) is that it takes more viscosity modifiers to make a 0w-40 synthetic oil than a 5w-40 or 10w-30. It is the viscosity modifiers that break down over time and can leave sludge. Given that the 0w-40 is a high quality base stock, and this oil is used by Austin Martin, Mercedes AMG, Porsche, and others as their factory fill oils, I don't think this is a real world issue. . (Note that Raventai and cary differ slightly here as I do not believe that the 0w-40 Synthetic oils made today have any risk of sludge problems.)

It is also worth noting that generally, for low RPM, hi stress engines you want a slightly heavier oil, this is why the 5w-20 seems okay for the Honda's.

I have been shying away from the Mobil Xw-30 oils because they are formulated on the light side of 30 weight, almost being 20 weight. If you are looking for a Xw-30 weight, look at Redline, Amsoil (I never thought I would recommend Amsoil), or others. I truly believe for any climate that a Xw-50 oil is overkill for the Landcruiser.

The idea that synthetics targeted at diesel's use a better base stock than synthetics made for combustion engines is not true. The difference between diesel and combustion oils is the additive and detergency packages. Diesels pollute the oil in different ways than gas engines. Example, Delvac 1 and Mobil 1, same manufacture, both made with Group IV & V base stocks, different additive package.

Synthetic blends- DON'T WASTE YOUR TIME. The synthetic “blends”; are a waste. Why, first they usually made by the same companies that call their group III+ base stock oil “Synthetic (Castrol Syntec (except the German stuff), Valvoline). They then take a blend of their “synthetic” and mix it with Group II base stock standard oil. The really crummy part is often the “synthetic” part of the oil is only 10-25% of the mix. I would either stick with a good mineral oil (Chevron) and change it every 3000-4000 or switch to synthetic and go 6000-7500.
If you insist on going this route, consider using a hi mileage oil instead which will likely have a higher proportion of Group III or Group IV base stocks than the “blends”.

Delvac 1 reports have been good. Mobil has just released their Mobil 1 5w-40 Synthetic SUV oil. Ignoring the name, is appears, and Mobil reps have unofficially confirmed that it is in fact repackaged Delvac 1. This is a great deal because delvac 1 is only available in 1 gallon containers and runs $6 a quart v. the new 5w-40 sells for $4.00-$5.00 a quart.

The Delvac 1 is considered a great oil. That said, the view is that for Gas engines that the Delvac has to many additives. The oil won't harm the motor, but other choices may be better. IF YOU HAVE A DIESEL this is the stuff to use. Also, a reason to avoid Delvac 1 is that it isn't exactly easy to find. A reason I tend to shy away from boutique oils.

Concerning 15w-50, there is really no need to run it. The big factor in oil breakdown is its High Temperature High Shear (“HTHS”) performance at 150c (closely replicates running conditions at the cam and bearings). Generally, Synthetics will have a much higher HTHS than minerals for the same weight. If you look at the specs for cars in Europe, especially Germany you will see gradual change. It used to be that they all recommended 20w-50 for temps above 32f. The reason was that 10w-40 and other lighter oils would shear down under hard running conditions and cause accelerated bearing and camshaft wear (exception the 15w-40 mineral oils which were recommended by Porsche for years and were used as factory fill in 911's from the 1970's until the 1990's). Now German cars used in Europe mostly require that the oil used meet ACEA A3 (some new VW and Audi's are moving to lighter weight A5 oils). The predominant requirement of A3 is that the HTHS be over 3.5, which M1 0w-40 (3.6), M1 5w-40 (4.1), and M1 15w-50 (5.1); note none of the Mobil 1 30 weight oils meet that standard. Note that all 15w-40 oils have an HTHS of at least 3.5.

The A3 rated oils simply provide better lubrication properties, both at startupcam and bearing protection at high temperatures,temps than 20w-50 mineral oils. At the same timenon A3 rated oils also provide better mileage and lower operating temperatures.. Note that A3 is mutually exclusive of A1 and A5. A1 and A5 oils have an HTHS of less than 3.5, so you cannot have an oil that A3 and A5 or A3 and A1 rated.

Bottom line is that you want to run the thinnest oil that provides protection. Reason is that as you get to heavy, wear rates increase again. Also heavy oils increase oil temperatures and do not transfer heat as rapidly. On average the sweet spot for low wear rates on oils appears to be at the high 30weight low 40 weight range (i.e. Mobil 0w-40, German Castrol 0w-30, Amsoil 30 weights, Redline 30 weights). Also note that some of the newer cars (specifically Hondas and the Big Ford V-10 engines) that specify 5w-20 oil from the factory are turning in incredibly low wear numbers on those oils.

Concerning using Mineral (Dino) oil and changing it every 2000 miles. Don't waste your time and money. The mineral oil is good for at least 4000 miles before it breaks down. If you live in a warmer climate (temps above 40f), run Chevron Delo 15w-40 ($1.25 quart) and change it every 6000.

There is no reason to change oil every 3000 miles, except to waste money. If you look at the UOA's on Mineral oils, you will see with the rare exception of certain motors that are very hard on oil that Mineral is good to 4000-6000 miles. The LC with an 8 quart sump easily allows for 4000-6000 mile changes on mineral.

You can run Rotella T synth out to 7500 with no problems, unless you are in artic conditions, very short trips where the motor never warms up.

The 5w-30; 10w-30 recommendation are because of US CAFE mileage standards. Same engine overseas recommends 40 & 50 weight for warm and hot weather. That said, you will not harm the motor using 30 weight oils, but will likely lower wear slightly and give an increase margin of safety under hard running conditions with a 40 weight.

I have also heard that synthetics need less polymer Viscosity Index Improvers, but for large spans most still need some, VII’s are the first portions of oil to degrade, Delvac 1 is suppose to be extremely sheer stable witch would indicate that is does not have any VII’s I am not sure how Exxon/Mobil did it, I am still waiting to see A virgin oil analysis over at bitog to be sure that the M1 suv is Delvac 1. if so it would be a great deal cheaper no driving to a truck stop to get it and in quart instead of gallon bottles, I have a similar climate to you and right now it looks like I will be running D1 when I get the new cruiser, before I decided to sell my truck I was going to use it in it. But I am going to stick with M1 in it

You will have no oil related problems if you change with dino every 3k, synthetics oil is better oil in almost every way except cost but will it pay off for you? No one can tell you how much longer your engine would last with synthetic vs dino, also you are more likely a head gasket, wreck, run out oil, transmission failure or the 1000 other things that can happen or just age of the body will cause you to get rid of it before the engine internals wears out, in witch case the extra expense is wasted, but for me the engine cleanliness improved gas mileage (very small but offsets some of the cost) longer drains and most importantly “that warm fuzzy-I'm doing something good for my car-feeling.” Make synthetic worth it for me

According to an article from BMW CCA Golden Gate Chapter, where the chief chemist from Redline Oils in a 3 hour product demonstration flat out stated that under normal conditions where oil is changed regularly, it is questionable if there is any increase in engine life by using synthetic. Advantages of synthetic are cold start, longer change intervals, and protection at the margin.

Synthetics may increase engine life (note that newer motors are getting much more demanding on oil and many REQUIRE synthetic because of their longer change intervals and need for high hths oils with moderate weights) but for most properly maintained motors, at what point? A LC motor with mineral oil changed every 5000 miles will go 300,000+ miles, so will the Synthetic stretch that to 350,000 miles? Does it matter? My only thought is that perhaps the synthetic will keep the motor running better longer through less wear. For example my Nissan Pathfinder has 185k and starts and runs like a champ. Is this from the lower wear by Mobil 1 or that I am anal about all maintenance?

.. For reasons unknown, even among the same motor design, some engines work better with one oil than another. There are those who have had great luck with 0w-40 and those who their truck sucks it down at 1 quart every 1000 miles. Same goes for the Rotella Synth. Try one of the above, if you have high consumption, then switch. Personally, I don't worry about the start up rattle, I have it and my UOA's were fabulous. As a guy at the local parts place said "all Toyota's do that, even our parts truck that has been doing it for 500,000 miles."

Amisol is a great product and I wouldn't hesitate to use it. I don't recommend it for a few reasons. 1) It is more expensive than Mobil 1, 2) in the UOA's I have seen, it doesn't perform any better than Mobil 1, and 3) it can be difficult to get for many

Based on the information I have seen there (bobistheoilguy.com), I will add a few more comments/suggestions.

1) Mobil 1 tends to be blended on the thin side of the weight scale. So their 10w-30 tends to be closer to a 10w-20, and the 0w-40 with a cst @ 100 of 14.3 is on the borderline of a 30w oil. Given that I would feel entirely comfortable running the 0w-40 in all climates and not be worried about it being to thick.

2) Mobil 1 formulas vary depending on the continent they are from. The sole exception to this is the 0w-40 which is a worldwide oil.

3) Castrol is now importing Syntec 0w-30 from Germany to the US and Canada. Unlike the Syntec which has been sold in the past in the US, this is not a Class III crude refined but a top grade Class IV PAO/Class V Ester stock oil. In addition this oil runs thick for a 0w-30 with a cst at 100 of 12.1 (compare that to the Mobil 1 30w with a cst of 10.0). The talk on the lists is that this may be the best 30weight oil available in the US. BE AWARE THAT YOU HAVE TO LOOK CAREFULLY TO GET THE CORRECT FORMULA OF THIS. The proper syntec (as opposed to the garbage) will be 0w-30 with a red label and on the back will say "Made in Germany.”Do not buy any other syntec besides this.

4) Amsoil is regarded as anything from snake oil to pretty good. Most of the oil lab testing doesn't show it to be anything spectacular; and

5) For those of you looking for heavier than Mobil 1 0w40 (which you shouldn't need), the new Redlineconsider Mobil 1 Truck and SUV 5w-40 with, which is slightly thicker and has a csthigher HTHS of 154.1 at 100, looks to be very promising according to the initial tests. This oil is made (to the best of my knowledge) from only Class V ester based stocks which are generally considered the best.

6) All of that said, the reason that most of the guys on the bobistheoilguy forum do oil testing (besides seeing how well is performs) is to see at what point the oil starts breaking down and should be changed. For the synthetics, it appears between 7500 and 15,000 miles is the proper interval. Factors that influence this are 1) oil capacity, the more the engine holds the further between oil changes, 2) driving conditions, 3) quality of the oil, and 4) the condition of the engine.

7) There is also an interesting consensus concerning oil weight on that board, and it is essentially that as a motor gets older and starts to burn oil, it is okay to go to a heavier weight even though the manufacture may not recommend it.​

Romer,
Thanks for the time you put into this. It's very good info.
Being brainwashed on Amziol that I have used for years, I was suprised to not find outstanding results from there oils.
Being an 80 owner and dealing with the "auto tranny" where do the ATF's rate in the recommended oil catagory?

On Amsoil, I think Cary said it well above, Amsoil's direct competition is Mobil 1, and from what I have seen neither has shown a consistent performance advantage over the other. This is not that surprising as both are Group IV (PAO, Polyalphaolefin) base stock with a quality additive package, being approximately the same oil I prefer Mobil 1 as it is widely available and in most cases cheaper.

Amsoil has a different distribution model, if you know someone who is a dealer you may be able to get it cheaper and easier, if so. and you like it, then use it,

I have not done a lot of research on ATF, I used Mobil 1 ATF in a previous vehicle and liked it so went with same in my 80, you do not go through as much ATF so the cost is less of a factor. although not exactly conclusive Mobil 1 ATF seams to hold its color and smell quite well, no leaks & no problems.

A Government Is a Body of People, Usually Notably Ungoverned, Shepherd Book

That rifle on the wall of the labourer's cottage or working class flat is the symbol of democracy. It is our job to see that it stays there. George Orwell

To the comment that the FZJ will go 300,000 plus miles with only dino changes at 5,000 miles. I am now taking care of my bro in law's with 297,500 (Feb '06) and it is living proof. Doesn't burn oil, doesn't smoke on startup, coast, wide open throttle and literally exhibits absolutely no operating parameters different from my 93 with 158,000 miles of 6200 mile average changes on strictly Mobil 1 since new. We bought ours within a few months of each other, so I know the history since day 1 of both.

Hypoid refers to the design of the gears as opposed to the oil. It would be more correct to say "oil for use with hypoid gears" as opposed to "hypoid gear oil". I don't remember the exact definition of hypoid gears at the moment.

Original owner 93 FZJ80,locked,blown,water/methanol injected(like a WWII fighter aircraft),lifted,winched,snorkeled,slidered,Sleeed ,moneypit. Balanced on a pin head. 95 FZJ80 trail truck (hers), 94 FZJ80 320K with a knock. 88 JDM BJ74 FRP, 2009 Dodge Challenger SRT8, 465 horse HEMI, 6 speed manual trans, cop-attracting-red. Kimberley Kamper and some Garands. It is not necessary for you to know what you are talking about, it is only necessary that you sound like you know what you are talking about.American Toyota

1) Redline Gear Lube 75w-90- Gear and Tranny Lube are where Redline made their name.

Click to expand...

what is your take on redline's heavy shockproof gear oil (<http://www.redlineoil.com/products_gearlubricants.asp?pvID=87&prodID=61&subcatID=20>)? this is what i have been using in my diffs / transfer case for a while... thanks,

Hypoid is a description of the ring and pinion gears in the axle, has to do with their sliding contact, this sliding contact makes for requirements on the oil used, you should look for gear oils that state GL-5 on the bottle, Gl-5 is a hypoid oil and then some and can be used in the axles and transfer case, all of the above meet GL-5 AFAIK

Some manual transmission do better with GL-4 than GL-5, Gl-5 can be too slippery for good operation of some kinds of synchro’s slowing shift time, I do not know if this applies to Toyota transmission or not but we do not get to worry about that in the US.

the other thing abotu gear oil is frictin modifier addative needed for some clutch type lockers and positraction units, our lockers having no clutches have no need for this addative.

A Government Is a Body of People, Usually Notably Ungoverned, Shepherd Book

That rifle on the wall of the labourer's cottage or working class flat is the symbol of democracy. It is our job to see that it stays there. George Orwell

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